Suggest Remedy To Relieve Burning And Itching In Vagina Due To Pads?

I am a 15 year old girl and I have started masturbating about 2 weeks ago. The problem is my vagina is really sensitive and if I buy the wrong pads whilst on my period I get a burning and itching irritation for about a month. Masturbating takes the pain away for about half an hour, then it comes back worse. What can I do to make it go away?